Clutch control mechanism



Nov. 28, 1950 T. H. THOMAS CLUTCH CONTROLMECHANISM 5 Sheets-Sheet 1 Filed Nov. 4, 1944 IN VEN TOR. 7/ /0M4J hf 7710mm ATTORNEY 3 Sheets-Sheet 2 T. H. THOMAS CLUTCH CONTROL MECHANISM WEE.

F w I Nov. 28, 195

F1196. Nov 4 19 Nov. 28, 1950 T. H. THOMAS 2,531,710

CLUTCH CONTROL MECHANISM Filed Nov. 4, 1944 3 Sheets-Sheet 3 IN V EN TOR.

ATTORNEY Patented Nov. 28, 1950 UNITED STATES PATENT OFFICE,

CLUTCH CONTROL MECHANISM Thomas H. Thomas, South Bend, Ind., casino: to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application November 4, 1944, Serial No. 561,844

1 Claim. 1

This invention relates in general to the clutch mechanism of an automotive vehicle and in particular to power means for controlling the operation thereof.

More specifically, the invention relates to pressure differential operated power means for controlling the operation of a combined centrifugal and spring operated clutch. To this end there is suggested a manifold vacuum operated motor operably connected to the spring operated pressure plate of the clutch,- said plate having mounted thereon centriiugally operated means supplemented by the operation of the clutch springs in effecting the desired smooth engagement of the clutch.

A further feature of the invention relates to the provision of power means for controlling the operation of the aforementioned combined centriiugal and spring operated clutch, said means being controlled in part by the means for operating the engine throttle of the vehicle: apropos the latter feature of the invention it is an object to so correlate the opening of the throttle and the clutch engaging operation of the power means as to insure an effective operation of the centrifugal means in engaging the clutch.

A further object of the invention is to provide a pressure differential operated motor operable, in controlling the clutch engaging operation of a combined centrifugal and spring operated clutch mechanism, to eilect two distinct stages of movement of the pressure plate, the first stage being relatively rapid and terminating when the driving and driven clutch elements are to a slight degree loaded by the spring means of the clutch, and the latter stage being relatively slow to effect, under unusual driving conditions, an operation of the clutch springs to supplement the clutch engaging action of the centriiugally operated weights.

Yet another object of the invention is to so construct and arrange the parts of the aforementioned mechanism as to correlate the timing of the operation of the centrifugal mechanism with respect to the timing of the operation of the clutch springs to the end that under ordia heavy torque for example when the car is heavily loaded or is going up an incline.

Yet another object oi. my invention is to provide power means for quickly and completely disengaging a combined centrifugal and spring operated friction clutch; for with a conventional type of centrifugal clutch the disengagement thereof is delayed, resulting in a slipping of the clutch and an undesired deceleration of the vehicle, when the accelerator is released and the car is travelling at a relatively high speed. With my invention, however, that is the combination of centrifugally operated means and spring operating power means for effecting the disengagement and controlling the engagement of the clutch plates, there is a complete separation of said plates immediately after control means, for example the accelerator and either a governor or transmission controlling shift lever, is operated to effect a clutch disengaging operation of the power means.

One of the most important objects of my invention is to provide power means for controlling the operation of a combined centrifugal and springoperated friction clutch said power means including a two-stage pressure differential operated motor for controlling the clutch engaging operation of the spring means of the clutch said motor being controlled by a three-way valve and by power operated valvular means for controlling the two stages of clutch engaging operation oi. said motor, the latter means being controlled in part by the three-way valve and being operative to efiect said second stage operation of the motor after a certain timed delay.

In general therefore it is the object of the invention to provide an automatically operable friction clutch structure operative to accurately simulate a skillful manual operation of said clutch to the end that the vehicle may be effectively accelerated under all conditions of service.

Other objects of the invention and desirable details of construction and combinations of parts will be apparent from the following description of a preferred embodiment of the invention, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a diagrammatic view of the clutch operating mechanism constituting the present invention;

Figure 2 is a sectional view disclosing in detail the structure of the combined centrifugal and spring operated clutch to be controlled;

Figure 3 is a fragmentary view disclosing a portion of the connection interconnecting the clutch, the clutch motor and the clutch pedal;

Figure 4 is an enlarged fragmentary and sectional view of a portion of the clutch structure of Figure 2 disclosing the clutch engaging springs;

Figure 5 is a diagrammatic view, largely in section disclosing the relative position of the parts of the mechanism when the clutch plates are slightly loaded by the clutch springs of the mechanism and just prior to the clutch engaging operation of the centrifugal weights of said mechamsm.

In that embodiment of the invention selected for illustration there is diagrammatically disclosed in Figure l a clutch mechanism l0 which is adapted to interconnect the internal combustion engine l2 of an automotive vehicle with a conventional change-speed transmission H, the latter being drivably connected by a propeller shaft IS with the driving wheels of the vehicle.

The accelerator ll of the vehicle is connected to a throttle operating crank l8 by means of a link II. a lever l3, and a link IS, the latter being provided with a pin at its end fitting with a slotted portion 9 of the throttle operating crank ll to a,

provide a lost motion connection My invention is directed to power means for controlling the operation of the clutch ll, the latter being of a combined centrifugal and spring operated type. As disclosed in Figure 2, a flywheel 20, drivably connected with the engine l2, constitutes the driving element of the clutch; and a disk 22, slidably keyed to the propeller shaft ll at 24 and provided with friction rings 26 constitutes the driven clutch element. The means for forcing the driven clutch element into driving engagement with the driving clutch element comprises a pressure plate 28, mounted within a clutch shaped housing 30 secured to the flywheel plate by'fastenings 32. A ring 34, mounted on the plate by a plurality of pins 36, constitutes, together with the plate, a pressure applying unit, said unit being normally urged to the left, to engage the clutch, by means of a plurality of angularly spaced clutch springs 38, Figure 4.

A plurality of angularly spaced centrifugally operated weight members 40 each having a leverlike shank portion 42 extending through the plate 38 into engagement with the ring 34, are supplemented by the clutch engaging action of the springs 38 at or above'a predetermined R. P. M. of the flywheel, the centrifugal force developed by the rotating weights serving to urge the weights outwardly in direct proportion to the angular speed of the flywheel and tending to force the ring from the plate and into engagement with the driven clutch element 26. Above the predetermined R. P. M. of the flywheel the clutch engaging springs 38 serve to supplement the clutch engaging operation of the weights 40. Springs 44 sleeved over the pins 36 between the plate 28 and stops 46, serve as return springs to keep the plate and ring together when the flywheel is static or below the aforementioned critical angular speed. The loading of the clutch is thus the additive result of the effects of the clutch springs 3| hav-- ing a constant maximum effect and the centrifugally operated weights '40, the eifect of the latter being a variable the value of which is a function of the R. P. M. of the flywheel.

The invention is specifically directed to power operated means for controlling both the disengagement and engagement of the aforementioned clutch, and in such fashion as to result in its most effective operation under various conditions of 4 service of the vehicle. The above described apecific clutch structure is not claimed herein.

To the above end there is provided a fluid pressure operated motor preferably a double-ended manifold vacuum operated motor 48 comprising a cylinder 50, pivotally secured to the chassis of the vehicle at 52, and a reciprocable piston element 84, the latter being operably connected to the pressure plate 2| of the pressure unit by a rod 58, crank It, slidable collar 60, lever operating finger members 02 and pins 84. The finger members 82 are fulcrumed intermediate their ends upon pins 08, secured to the housing member 30. The pressure plate may also be operated to disengage the clutch by means of a conventional clutch pedal 68 interconnected with the sleeve Oil by linkage III. A spring ll serves to maintain the pedal 68 in its oil position against a stop H.

One of the most important features of my invention resides in the valvular mechanism for controlling the operation of the aforementioned clutch operating motor. To this end there is provided a three-way valve 12 of conventional design and therefore not disclosed in detail, said valve being operated by a solenoid 14 to open the valve, that is, connect a compartment 18 of the motor 48 with the intake manifold 18 of the engine I2 via a conduit 80, valve 12, and a fitting 82, Figure 5. The three-way valve is also. of course, operated by a spring, not shown, to close the valve, that is, vent the compartment It to the atmosphere via an air cleaner '4, the valve 12 and the fitting 82.

The solenoid 14 is preferably controlled by an accelerator operated switch It, a grounded vehicle peed responsive governor operated switch ll and grounded switches II and I2 actuated by a transmission and clutch controlling shift lever 04 conveniently mounted beneath the steering wheel 96 of the vehicle. As disclosed in Figure l the grounded governor operated switch 88 is wired in series with the solenoid 14 and the accelerator operated switch 86, the latter switch being wired to a grounded battery 98. A cut out switch ill and the ignition switch I02 of the ignition system 01' the vehicle are interposed in series in the wiring interconnecting the battery and accelerator operated switch. Describing now the shift lever operated mechanism for operating the switches 90 and 02, the shift lever 94 is preferably connected with said switches and shift rail actuating cranks I! and 3| by the force transmitting links and levers disclosed in Figure 1. Describing the operation of this force transmitting means and the parts thereof. a spring 23 interposed between a stop 2| Qxedly secured to the steering post 21 of the vehicle and a stop 29 fixedly secured to a shaft ll serves to bias said rod downwardly to the position disclosed in Figure 1. Now to the lower end of the rod 3| there is fixedly secured a crank 33 through which extends a pin 35; and when said rod is inoved downwardly by the spring 23 one end of said pin extends within an opening 31 in a floating crank 19. To one end of the crank ll there is plvotally connected a rod 4|, said rod being pivotally connected at its other end to the end of the crank l9. This crank when rotated clockwise serves to actuate other force transmitting means within the casing of the three speeds forward and reverse transmission l4 to establish the transmission in its high gear setting; when said crank is rotated counter-clockwise the transmission is established in its second gear setting.

The crank 2| when rotated clockwise serves to -a,sar,71o.

, rotatably mounted on the shaft 3i which is bodily movable through said crank. This crank is provided with an opening 41 to receive one end of the pin II.

When the driver wishes to establish the transmission in its high gear setting he rotates the shift lever 84 counter-clockwise and this operation serves to rotate the floating crank 39. Now the switch 82 is preferably so constructed that the force necessary to close the same, that is the force necessary to compress a spring within the switch connected to its movable contact, is less than the force necessary to effect the initial movement of the high second shift rail. It follows therefore that the initial high gear move ment of the shift lever 94 results in a pivoting of the crank 39 about its connection with the rod ii; and this operation results in a closing of the clutch controlling switch 92. Continued movement of the shift lever, that is the movement after the switch 82 is closed and there is no possible further movement of a link I! interconnecting the crank 39 with saidswitch, results in a pivoting of said crank about its pivotal connection with the link 49; and. this operation results in the operation of the transmission to establish the same in its high gear setting. After this setting is established the driver removes his hand from the shift lever whereupon the aforementioned spring within the switch 92 operates to open said switch. This switch is so constructed that the same is also closed when the driver moves the shift lever 9| to establish the transmission in its second gear setting; and the spring means within said switch also functions to open the same when the second gear setting of the transmission has been established and the driver removes his hand from the shift lever.

Describing the operation of the switch mechanism to establish the transmission in either reverse gear or low gear the driver first rotates the shift lever ,94 upwardly in a plane perpendicular to the plane of the steering wheel 96; and this operation serves to bodil move the shaft 3i upwardly against the tension of the spring 23. The upper end of the pin 35 is by this operation moved into the opening 41 and a subsequent rotation of the shift lever, either to establish the transmission in reverse or low gear, results in a rotation of the cranks l and 2| to effect one or the other of these settings of the transmission.

The shaft Si is provided with a recessed portion H which receives a pin 53 operably connected to the grounded switch 90; and as will be obvious from an inspection of Figure 1 when the shaft 3! is moved upwardly, in the operation of establishing the transmission in either reverse or low gear, the switch 80 is closed by virtue of the forcingof the pin 53 to the left, Figure 1, when the end of said pin is forced out of therecess 5| and onto the full bodied portion of the shaft.

There is thus provided, by the above described shift lever operated switch operating mechanism. means, cooperating with the accelerator operated switch 88, for effecting a clutch disengaging operation of the motor 48 during the first increment of movement of the shift lever as it is moved to establish the transmission in any one of nism are preferably so constructed and arransed that the clutch is disengaged before the transmission is operated. It is to be noted that the switch operating force transmitting means of my invention is such as to eifect a closing of the switch mechanism when the shift lever is moved in either one of two different planes. The clutch control mechanism of my invention may be incorporated in the power plant of a vehicle which includes a kickdown type of selective gear transmission of the day, that is a transmission which may, by a manual operation of a shift lever, be established in any one of a plurality of forward gear settings or a reverse gear setting; and after a forward gear setting is established then a vacuum and spring operated kickdown motor unit. controlled by a vehicle speed responsive governor and the accelerator of the vehicle, takes over the operation of said transmission. In this type of well known transmission mechanism incorporated on cars now in operation, the kickdown on downshift operation of the motor unit is facilitated by a momentary disabling of the ignition system of the engine; and the power plant including such a mechanism may also include a fluid coupling Referring now to Figure 5 disclosing the motor 48 and valvular means for controlling said motor, there is provided power operated valvular means for cheating a two-stage clutch engaging operation of said motor. The first stage valve of said valvular means, which is power operated by the operation of the piston 54, comprises a hub portion Iii! of an end plate "Got the motor which hub portion cooperates with a slot "I in the connecting rod 86 interconnecting the piston it with the clutch operating crank II. A second stage valve and power means for operating the same includes a pressure differential and spring operated motor IIO comprising a two-part casing II! and a power element ill. The motor therefore includes a chamber H6 and a chamber III, the latter housing a spring I20 biasing the power element to the left, Figure 5. The power element is provided with a relatively small opening I}! in its central portion, the function of which is described hereinafter. Housed within the spring I20 there is provided another spring I which is interposed between one face of a relief valve member III, that is the second stage valve, and one face of the power element Ill. The valve member I26 is forced upon a seat III, to close off a valve port I", when the motor III is vacuum energized, that is, when the chamber III is partially evacuated. The port III! is connected to a chamber I32 of the motor I: by a conduit ill; and the chamber us of the motor H0 is connected to the chamber 16 of the motor 48 by a conduit I".

There is thus provided power means for operating the second stage valve for when the motor ill is vacuum energized, by an operation or the three-way valve I2 to effect the clutch disengaging operation of the motor 48, then the chamber I i8 is partially evacuated resulting in a movement of the power element Ill to the right, Figure 5, to close the valve. I28. This movement of the power element is effected as a result of a differential of pressures acting upon the same; for when the air is drawn out of the chamber Ill air is admitted to the chamber Ill via a check valve I38.

When the chamber H8 is vented to the atmosphere, as a result of the clutch engaging operation of the three-way valve 12, then the motor its four gear settings. The parts of the mecha- III is spring energized, the spring I serving to move'the power element I I4 to the-left, Figure 5, and this operation makes possible an opening of the. second stage relief valve I26. This opening of the latter valve and the remainder of the operation of the mechanism to effect a second stage operation of the clutch engaging operation of the motor 48 will be described in detail hereinafter.

Describing now the complete operation of the clutch controlling mechanism constituting my invention, with the accelerator released, the vehicle at a standstill and the engine dead, the governor operated and accelerator operated switches 88 and 88 are closed, accordingly, the solenoid I4 is energized to open the three-way valve 12. However, the gaseous pressure within the intake manifold is at this time equal to the pressure of the atmosphere, accordingly, the motor is not energized.

- Now when the engine is started, the intake manifold is immediately partially evacuated by virtue of the pumping action of the engine pistons, accordingly, the compartment I6 of the motor 48 is also partially evacuated; and this results in a movement of the piston 54 to the left, Figure 5, to effect a movement of the pressure plate of the clutch away from the driven clutch plate. This movement of the piston is effected inasmuch as the same is then subjected to a differential of pressures, the compartment I32 of the motor being maintained at atmospheric pressure by virtue of the operation of a check valve I mounted in the end plate I06 of the motor. The driver will then probably establish the transmission in its low gear setting by an operation of the shift lever 94 and after this operation is effected he will then depress the accelerator to effect an engagement of the clutch to get the car under way. Describin the clutch engaging operation of the motor 48, the first increment of movement of the accelerator serves to open the switch 88; and the construction and arrangement of the parts of the mechanism, particularly the construction of the lost motion connection 9, is such that said switch is opened before the throttle is opened. Now with the opening of the switch 86, the solenoid I4 is deenergized thereby permitting the spring within the valve I2 to close said valve, that is, effect a venting of the compartment-I8 to the atmosphere; and when saidcompartment is vented to the atmosphere, this operation initiates a clutch engaging movement of the piston 54 under the action of the several clutch springs 38. The piston is then moved to the right, Figure 5, the air in the compartment I32 being pushed out of said compartment via the slot I 08 in the connecting rod 56.

' When the piston has moved a certain distance to the right the slot is covered by the hub portion I04, all as disclosed in Figure 5, whereupon the movement of the piston is arrested. Now' the length of the slot I08 is so determined and the remainder of the parts of the mechanism are so constructed and arranged that this first stage operation of the valve means is completed when the pressure plate of the clutch has moved suihciently to effect a slight loading of the driving and driven clutch plates; and this operation is effected before or at substantially the same instant that the opening movement of the throttle is initiated. It follows, therefore, that the clutch plates are to a degree loaded when the operation of the centrifugally operated weights is initiated. If at this time the R. P. M. of the engine is not high enough to effect a clutch engaging'operation of the centrifugalthe ring 34 of the pressure plate unit to effect the engagement of the clutch.

. Now, as previously described, when the threeway valve" is closed to vent the chamber III of the motor III! to the atmosphere, the spring I 20 immediately functions to make possible an. opening of the valve I26. This opening of the valve is, however, delayed for a certain time, this delay being effected by virtue of the time required to equalize the gaseous pressures in the chambers II 8 and H8; for after the completion of g the first stage of clutch engaging operation of the motor 48, which operation is described above,,

then the clutch springs continue to act to force the piston 54 to the right, Figure 5, thereby pushing air out of the chamber I32 of said motor. This operation tends to unseat therelief valve I26 against the tension of the spring I24; however, this unseating operation is delayed until the load on said spring is sufllciently reduced by the aforementioned bypassing of air from the chamber II6 to the chamber 8. This bypassing is, of course, effected by virtue of the opening I22 in the power element II4.

It follows, therefore, that the time of opening of the valve I26 is determined by several factors including: the strength of the springs I20 and I24, the gaseous pressure within the chamber IIB, the size of the port I30, the strength of the clutch springs 38, and other factors.

The parts of the mechanism are preferably so constructed and arranged and so operative that the opening of the second stage valve I26 to initiate the second stage operation of the motor 48 is delayed until after the throttle has been opened to a degree sufficient to eflect all. normal clutch engaging operations of the clutch;,

but after a relatively short time the clutch springs, by virtue of the second stage operation.

of the motor 48, further supplements the clutch engaging operation of the centrifugal weights 40, thereby insuring a loading of the clutch plates that will prevent the clutch from slipping under all conditions of service.

There is thus provided a clutch mechanismwhich insures a smooth start of the vehicle from rest, the clutch springs 38 supplementing the clutch engaging operation of the weights 40. If the vehicle'is perchance heavily loaded, then the engine will probably be slowed down in getting the vehicle under way; and this so-called laboring of the engine results in a slipping clutch inasmuch as the weights 40 exert a clutch engaging force which is directly proportional to the speed of the engine. The clutch springs 38, however, come into action with the above described second stage operation of the motor 48 to supplement the operation of the weights thereby insuring sufficient loading of the clutch plates to prevent their slipping.

i The vehicle being then under way, the driver will release the accelerator and then operate the moves his hand from the shift lever thereby opening one or the other of the switches 90 or 92 to thereby efiect an operation of the three-way valve 12 and initiate the above described clutch engaging operation of the motor 48. Subsequent depression of the accelerator will then, as described above, efiect the clutch engaging operation of the weights 40.

When the vehicle is slowed down below a certain speed, then the governor operated switch 88 is closed and, if the accelerator is at the time released to close the switch 86, then the motor 48 is again energized to effect a disengagement of the clutch mechanism.

There is thus provided means, including the clutch springs 38 and the motor 48 for operating the same, for supplementing the clutch engaging operation of the centrifugal weights 40 to insure the desired acceleration of the vehicle and prevent the clutch plate wearing effect of a slipping clutch when the engine is laboring.

insure a disengagement of the centrifugal clutch means, and thereb obviate any undesirable deceleration of the vehicle, when the accelerator is It is also to be noted that the motor 48 serves to r suddenly released when the vehicle is traveling at a relatively high speed.

While one illustrative embodiment has been described, it is not my intention to limit the scope of the invention to that particular embodiment, or otherwise than by the terms of the appended claim.

I claim:

In an automotive vehicle provided with a centritugal and spring operated friction clutch, power means for controlling the operation of said clutch including a pressure differential operated motor having two control chambers therein, valvular means for controlling the operation of said motor comprising a three-way valve operable in part to eifect the clutch disengaging operation of the motor, a first stage valve and a second stage valve, power means for controlling the operation of the second stage valve including a pressure differential operated motor which includes a double-ended casing and a power element having an opening in its center, a fluid transmitting conduit interconnecting one chamber of the latter motor with one chamber of the first mentioned motor and another fluid transmitting conduit interconnecting the aforementioned chamber of the second mentioned motor with the other chamber of the first mentioned motor.

THOMAS H. THOMAS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PA'I'ENTS Hill Dec. 26, 

